基于局部非热平衡模型的发汗冷却过程的数值模拟

本文对水平槽道内发汗冷却建立了包括主流区、多孔壁面区和致密壁面区在内的完整的物理模型和数学描述, 对耦合传热过程开展了数值模拟,对平板发汗冷却的机理进行了深入的研究。研究表明:发汗冷却减小了壁面处的速度梯度,使下壁面边界层明显增厚;随着冷却流体的注入,壁面处的湍流应力明显增大;湍流应力的最大值向没有发汗冷却的壁面一侧偏移,并且增加了最大湍流应力;边界层的增厚使得发汗冷却区域壁面摩擦阻力系数降低。随着冷却剂流量的增大,壁面温度也随之下降;数值模拟结果与实验结果较好地吻合。

NUMERICAL INVESTIGATION ON TRANSPIRATION COOLING BASED ON LOCAL THERMAL NON-EQUILIBRIUM MODEL

Transpiration cooling physical model in a rectangular flow passage, including the main flow region, the porous plate region and the impermeable wall region was established. The heat transfer characteristic was investigated numerically. The results showed that the velocity gradient decreased at the region near the wall and the thermal boundary layer increased evidently with the injection of the coolant. The turbulent stress at the near wall region with the porous wall increased rapidly and the maximum turbulent stress also increased because of the coolant injection. The wall temperature decreased sharply with the increase of the blowing ratio. The numerical results corresponded well to the experimental data.